• CAM-Impingement: refers to the form error in the area of the transition from femoral head to femoral neck. The deformed femoral neck – femoral head transition, pushes with its hump against the edge of the acetabulum.
• Mechanical conflict between the transition of the femoral head and the femoral neck.
• As a result, the cartilage of the acetabulum slowly detaches from the underlying bone and is depleted.
• The consequences are the beginning of osteoarthritis, which progresses without treatment and can result in joint replacement.
• The joint lip (labrum), which has an important sealing function around the femoral head, is also damaged (labrum tear).
• CAM impingement is more common in men and can damage the joint from the early age of 16 years.
• This is particularly significant for athletes, due to the increased physical strain.

Either the upper front edge of the acetabulum protrudes clearly or the acetabulum is too deep (coxa profunda, protrusio coxae).
This leads to a limitation of the mobility of the hip joint. The head of the femur is literally put in a pincer. This form leads to slow, extensive wear of the joint. It is more common in women and typically causes pain from the ages of 30 or 40.

The combination between CAM and pincer impingement is the most common.

Wo bereits der Knorpel oder die Gelenklippe beschädigt ist (Bildgebung: arthro-MRI), ist das Vorhandensein des Hüftimpingements sehr wahrscheinlich.
Der akute Schmerz kann nach einigen Wochen, Monaten abklingen. Die Knochendeformität ist aber weiterhin vorhanden, der Knorpel und die Gelenklippe wird weiter abgenuzt, beschädigt, bis es den kritischen Ausmass erreicht.
Dann liegen meistens schon relevante Knorpelschäden vor, welche wiederum Schmerzen auslösen können.
In diesem Zustand ist es möglich, dass nur die gerissene Gelenklippe zu behandeln ist (Refixation). Wenn aber bis zum Knochen reichende Knorpelschäden vorhanden sind, muss diese wieder aufgebaut werden.
Aus diesem Grund liegt der Akzent auf der Prevention und Früherkennung.
Lieber eine Abklärung durch einen Spezialisten, als eine früh auftretende Hüftarthrose!

50-60% der Patienten, die wegen der starken Abnützung einen künstlichen Hüftgelenk brauchen, haben früher ein nicht behandeltes Hüftipingement gehabt.

Die Deformität, welche zum Hüftimpingement führt ist häufig beidseits vorhanden, aber selten beidseits gleichzeitig schmerzhaft.
Wenn es auf den konventionellen Röntgenaufnahmen Zeichen eines Impingements sich erkennen lassen, ist es sinnvoll eine Arthro-MRI Aufnahme zu machen, um eine Schädigung des Gelenkknorpels rechtzeitig zu erfassen.
Wenn es in einem Jahr keine Beschwerden in dieser Hüfte auftreten, dann ist es empfohlen das MRI zu wiederholen.

Conservative therapy

Conservative therapy is carried out through physiotherapy (centering the joint, strengthening the muscles around the joint). After often frustrating conservative treatment, arthroscopic correction (keyhole surgery) of the bone deformity and repair of the existing damage is the method of choice.
Open surgical hip luxation is not necessary in the vast majority of cases.
A high-ranking publication shows that arthroscopic surgery is clearly more successful and provides clinically significantly higher patient satisfaction than physiotherapy alone. (REF Lancet Ashley)

https://www.ncbi.nlm.nih.gov

Surgical Therapy – Hip Arthroscopy

Hospital stay: 2 nights.
Spinal or general anaesthesia.

Before the operation, the hip is brought into the painful position and the area where there is a mechanical conflict between the edge of the acetabulum and the neck of the femur is marked. During the operation 2-4 short skin incisions (1-1.5 cm) are made. The hip joint is shown with a special video camera. The joint capsule is opened gently. To be able to look into the acetabulum, pulling on the leg is necessary to pull the femoral head out of the acetabulum.
In the case of an impingement of the “pincer” type, the overhanging edge of the acetabulum is shortened and the joint labrum is reattached (sutured). If the joint labrum is torn off, but no cup edge correction is necessary, it is sutured.

Preserving the joint labrum is a must today, as patient satisfaction after suturing versus removal is much higher. (REF C. Larson) If there is a cartilage defect that extends to the bone, the cartilage is regenerated there. This is done with the help of the patient’s own stem cells and, if necessary, a collagen membrane after microfracturing (AMIC).

Special instruments are used to correct the bone deformity at the femoral neck/head junction according to the above-mentioned marking. This is the essential part of the surgery, because the most common cause of pain after the surgery is insufficient correction in this area.

A Method for Capsular Management and Avoidance of Iatrogenic Instability: Minimally Invasive Capsulotomy in Hip Arthroscopy

In any case, the joint capsule is sutured back together to restore the anatomical situation here as well. This prevents iatrogenic instability (caused by medical action), which is extremely important in young patients. In rare cases (less than 5%) open surgical hip dislocation is recommended.

• Infection: very rare < 1%.
• Ossification in the soft tissue (joint capsule) (heterotopic ossification): 1-2%. Mostly accidental finding, if painful, it can be easily removed with arthroscopic surgery. To prevent this complication, patients receive 75 mg indomethacin for 2 weeks after surgery
• Stress fracture / stress fracture of the femoral neck: 0.1% (of 1000 operations 1x)
• Reduced blood flow and death of the femoral head: professional rarity